1. Field of the Invention
The invention relates to a window air bag system installed in a vehicle and a method of mounting the same.
2. Description of the Related Art
In a window air bag system as an example of the related art, an air bag designed to be inflated into the shape of a curtain in a lateral region of a passenger compartment by being supplied with gas from an inflator is stored in a folded state along a pillar portion and a roof side rail portion (an upper edge of a door opening of a vehicle body). For example, JP(A) 3052085 discloses such a window air bag system.
In the window air bag system disclosed in JP(A) 3052085 described above, a multitude of sheet ribs functioning as energy-absorbing members are integrally formed on a back surface of an A-pillar garnish (i.e., an inner surface of a front pillar garnish). The sheet ribs are located behind the folded air bag, and a passage for assisting deployment of the air bag is formed between the sheet ribs and the A-pillar (the front pillar). Each of the sheet ribs facing the passage has a curved surface that is not squarish but smooth.
In the window air bag system disclosed in JP(A) 3052085 described above, the multitude of sheet ribs are disposed in the longitudinal direction of the A-pillar at intervals of a predetermined distance. Thus, while the air bag is being deployed, it is likely to be trapped by the sheet ribs. That is, the direction of deployment of the air bag cannot be stabilized easily. Also, the sheet ribs require a long stroke to ensure desired energy-absorption performance, and the passage for assisting deployment of the air bag constitutes an idle-running stroke (a stroke that does not contribute to the absorption of energy). Thus, in order to achieve desired energy-absorption performance in the sheet ribs, the sheet ribs must be enlarged so that the A-pillar garnish protrudes considerably into the passenger compartment. If the A-pillar protrudes considerably into the passenger compartment, disadvantages in the availability of a space in the passenger compartment, visibility, and the degree of ease with which a passenger can get on and off the vehicle are caused.